Composition and method for the control of diabroticite insects

ABSTRACT

Diabroticite insects, in particular the corn rootworm, are major pests of corn as well as a variety of other agricultural crops. The invention describes an aqueous composition which is effective as an insectide for the control of Diabroticite insects and contains a photoactive xanthene dye, such as phloxine B, as a toxicant and a cucurbitacin-containing feeding stimulant. Additives such as a starch thickener and an adherent may also be included in the composition.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The corn rootworm (CRW) is a major threat to the production of corn inNorth America. Costs associated with attempts to control the pestcombined with monetary losses due to crop damage can exceed $1 billionper year. Moreover, the CRW causes an additional $100 million in damageand control costs on cucurbits, peanuts and soybeans; adult insects havecaused considerable damage to many fruits and have been implicated ascarriers of some plant diseases as well.

Chemical pesticides for the control of the CRW pest complex are appliedto 12-16 million hectares per year. These chemicals often have beenapplied as a preventive measure, sometimes unnecessarily, thusincreasing the health risks imposed on the general population as well ason livestock and other farm and domestic animals and wildlife.

The need for an effective agent for the control of CRW which is alsoenvironmentally safe is thus well-established. This invention relates toa toxicant-bait formulation effective for controlling corn rootworm andto its method of use.

2. Description of the Relevant Art

An interesting relationship between insect herbivores and their hostplants is the phenomenon exhibited by insects feeding compulsively onphytochemicals that are toxic to other insects. This phenomenon occursbetween CRW and their ancestral plant hosts, the Curbitaceae. Theseplants produce very bitter compounds, cucurbitacins, which arephagostimulants for many of the CRW pest species (Metcalf, R. L. 1986.J. Chem. Ecol. vol. 12, pp. 1109-1124; Metcalf and Lampman. 1989. J.Econ. Entomol. vol. 82, pp. 1620-1625; Tallamy and Kriachik. 1989. Amer.Nat. vol. 133, pp. 766-786; Metcalf and Rhodes. 1990. In: Biology andutilization of the cucurbitaceae. Bates et al., eds. Comstock, Ithaca,N.Y.). No evidence of acute toxicity exhibited by the compounds has beenproduced (Tallamy and Halaweish. 1993. Environ. Entomol. vol. 22, pp.925-932).

There has been a major effort to replace ineffective and environmentallyundesirable soil insecticides with baits laced with cucurbitacins andtoxins (Metcalf et al. 1987. J. Econ. Entomol. vol. 80, pp. 870-875;Lance, D. R. 1988. J. Econ. Entomol. vol. 81, pp. 1359-1362; Weisslinget al. 1989. Entomol. Exp. Appl. vol. 53, pp. 219-228; Lance and Sutter.1990. J. Econ. Entomol. vol. 83, pp. 1085-1090; Lance and Sutter. 1991.J. Econ. Entomol. vol. 84, pp. 1861-1868; Weissling and Meinke. 1991.Environ. Entomol. vol. 20, pp. 945-952; Brust and Foster. 1995. J. Econ.Entomol. vol. 88, pp. 112-116). Lacing the baits with cucurbitacinscauses the beetles to compulsively feed on them, and they die from theinsecticides present in the composition. The increased feeding broughton by the presence of the cucurbitacins has resulted in a reduction inthe amount of insecticide necessary for an effective formulation by90-95%. These baits are pest specific and are capable of killing 99% ofthe beetles consuming them (Tallamy and Halaweish, supra). Carbaryl, asemiochemical-based insecticide bait specific to CRW, for example, hasbeen developed by a research team comprised of entomologists from USDA,ARS, universities, and industry (Chandler et al. 1995. In: Clean water,clean environment. 21st centure team agriculture, working to protectwater resources. Conf. Proceed. vol. 1, pp. 29-32) and is currentlyunder commercial development. The baits are currently being evaluated inareawide Integrated Pest Management (IPM) programs for CRW control onlimited corn acreage in the Corn Belt (Chandler et al., supra).

The goal of agronomists in refining IPM practices is to rely less onsynthetic chemicals in baits and, if possible, to find other approachesto managing the CRW (Butler, R. E. 1992. Seed World. vol. 130, pp.8-10). Various attempts have therefore been made to develop formulationseffective for controlling corn rootworm. The baits laced withinsecticides and feeding stimulants, e.g. those reported by Metcalf etal., supra, are prepared from Cucurbita fruits which were dried, groundand impregnated with insecticides and volatile attractants. These baitswere then scattered over plots of sweet corn, with some of the bait onthe leaves and silks of the ears of corn. Lance and Sutter (1992. J.Econ. Entomol. vol. 85, pp. 967-973) also described a bait formulationcontaining an insecticide, a feeding stimulant and volatile attractants.In both instances, volatile attractants were included sincecucurbitacins, although recognized as powerful feeding stimulants, arenot effective as attractants. Delivery of the insecticide was thereforeaccomplished by first attracting the insect, then stimulating it to feedon the insecticide-laced bait.

Other compositions and methods have also been utilized in attempts tocontrol the corn rootworm. Guss et al. (U.S. Pat. No. 4,565,695, 1986)suggest the use of synthetic pheromone for mating disruption or for usein combination with larval insecticides. Doane et al. (U.S. Pat. No.5,464,618, 1995) describe a gustatory stimulant comprising dried andpowdered plant material containing cucurbitacins, a lubricant and anadherent to be used in combination with an insecticide for adultbeetles. Munson et al. (U.S. Pat. No. 5,571,522, 1996) describe afeeding stimulant to be used in combination with an insecticide wherethe feeding stimulant is corn germ.

All these various approaches have suffered from a lack of consistency inthe delivery of the insecticide to the targeted insect. Whilecucurbitacins are potent feeding stimulants, they do not serve asattractants at all, so the targeted pests must be in the immediatevicinity of the compounds in order for them to be effective. Dryformulations have thus resulted in a substantial portion of theinsecticide being wasted because it is never consumed. This waste isdeleterious not only because of cost and ineffectiveness, but alsobecause it results in insecticide remaining in the fields to contaminatethe soil, ground water and other sources of water such as lakes, riversand streams.

SUMMARY OF THE INVENTION

We have now discovered a composition which is consistently effective forthe control of corn rootworm and at the same time is environmentallysafe. The composition comprises cucurbitacin feeding stimulants and atoxicant in aqueous solution, where the toxicant compriseswater-soluble, photoactive xanthene-type dyes.

In accordance with this discovery, it is an object of the invention toprovide a composition for the control of Diabroticite insects, such ascorn rootworm.

It is also an object of the invention to provide a method of controllingcorn rootworm by applying the composition in amounts effective forreducing the population of Diabroticite insects, such as corn rootworm.

Other objects and advantages of the invention will become readilyapparent from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the effects of the various components of the composition onsouthern corn rootworm (SCR) mortality.

FIG. 2 shows the effects of varying concentrations of dye on SCRmortality both with feeding stimulant (FIG. 2a) and without feedingstimulant (FIG. 2b).

FIG. 3 shows the effects of varying concentrations of dye on SCRmortality when exposed to fluorescent light.

FIG. 4 shows the effects of varying concentrations of dye on SCRmortality when exposed to sunlight.

FIG. 5 shows the effects of two different concentrations of feedingstimulant (5% and 0.25%, w/v) and two different exposure time lengths(48 hours and 144 hours, respectively) on western corn rootwormmortality.

DETAILED DESCRIPTION OF THE INVENTION

The corn rootworm pest complex (subfamily Galerucinae) is comprised oftwo taxonomic groups, Virgifera and Fucata. The Virgifera group beetlesoverwinter as eggs in the soil and are univoltine. This group iscomprised of northern corn rootworm (NCR), Diabrotica longicornisbarberi Smith & Lawrence, from the upper Mississippi Valley; westerncorn rootworm (WCR), D. virgifera virgifera LeConte, from the MidwesternU.S.; and Mexican corn rootworm (MCR), D.v. zeae Krysan & Smith, fromthe south central U.S.

The Fucata group beetles overwinter as adults and are multivoltine. Theyinclude the western spotted cucumber beetle (WSCB), D. undecimpunctataundecimpunctata Mannerheim, ranging from the far western U.S. into theupper Baja Peninsula; the banded cucumber beetle (BCB), D. balteataLeConte, from the southeast U.S.; and the southern corn rootworm (SCR),D.u. howardi Barber, commonly known as the spotted cucumber beetle inthe adult stage and ranging east of the rockies from southern Canadainto Mexico.

Both larvae and adults are responsible for extensive feeding damage. Forexample, larvae of SCR hatch from eggs of overwintering adults andeither feed on seedling corn roots or bore into the base of the stem.They also attack peanut crops by penetrating the developing peanut andeither consuming it or facilitating attack by disease-causingmicroorganisms.

After feeding, diabroticine larvae pupate and emerge from the ground asadult beetles. Multivoltine species (e.g. SCR) can produce up to threegenerations a year. The univoltine beetle (e.g. NCR and WCR) life cyclebegins with eggs laid below the surface of the soil in the fall. Inearly spring, the larvae hatch and begin to feed. Beetles emerge frommid-July through August, with male beetles emerging about 1 week beforethe females.

Attempts have been made to control CRW in both the larval and adultstages with dry formulations, but this approach has generally beenproblematic with respect to actual delivery of insecticide to thetargeted pest. In order for the insecticide to be effective, it must beingested in sufficient amounts to kill the insect and enough of thetargeted insects must ingest enough insecticide in order to reduce, i.e.control, the insect populations to tolerable levels. In order toovercome this problem, investigations were carried out on aqueous-basedtoxicant-bait formulations which could be applied more uniformly onplants where beetles were more active and feeding would be preferred.

A water-soluble toxicant was required in order for the toxicant not onlyto be evenly distributed over the area intended for treatment but alsoto present a food more palatable to the insect. Various toxicants werestudied, and xanthene-type dyes were found to meet the requirements forsolubility and efficacy. Photoactive xanthene-type dyes exhibitedparticularly desireable properties due to activation of toxicity uponexposure to visible light. Fluorescein and the fluorescein derivativesproved especially useful, with the halogenated fluoresceins beingpreferred. Useful dyes include but are not limited to rose bengal,phloxine B, erythrosin B and eosin. It was also found that more than onedye may also be used in combination. Xanthene-type dyes are consideredthose dyes having xanthene as the basic structure with substituentswhich confer the photoactive property.

While not wishing to be bound by theory, it is believed thatlight-activated toxicity involves a transfer of energy, causing cellulardamage which is lethal to the insect (Heitz, J. R. 1982. In: Insecticidemode of action. Academic Press, Inc., herein incorporated by reference).The degree of halogenation of the parent fluorescein compound enhanceslight-activated toxicity. In addition, the dyes affect the insects froma developmental standpoint to some degree, and halogen content appearsto play a role in this effect.

Environmentally, the xanthene-type dyes are relatively benign since theyare generally non-toxic to non-target organisms, and they have arelatively short lifetime due to photodegradation.

In order to ensure that a sufficient amount of the dye is ingested bythe insect, the addition of a feeding stimulant to the insecticidalcomposition is important. Although cucurbitacins were previously usedmostly in dry formulations, they were known to be particularly effectivefeeding stimulants. Studies were thus carried out to determine if theyretained effectiveness when used in combination with the water-solublephotoactive dyes. Experiments were conducted to 1) confirm the advantageof the presence of feeding stimulant, 2) determine an effectiveconcentration range of dye and feeding stimulant and 3) investigate theeffects of light on the efficacy of the insecticidal composition.

Initial studies tested dye concentrations in the presence and absence offeeding stimulant and with a starch thickener. Groups of SCR wereexposed up to 24 hours to solutions containing dye alone, feedingstimulant alone or a combination of both dye and feeding stimulant (FIG.1). Results at 24 hours showed a significantly higher number of deadadults present in the group exposed to the combination of dye andfeeding stimulant (80%) than either the dye group (15%) or the feedingstimulant group (3%).

Various concentrations (from about 0.05% to about 5%) of dye were alsotested against the SCR with (FIG. 2a) and without (FIG. 2b) the feedingstimulant. Results at 24 hours (FIG. 2a) indicate significant increasesin dead adults even at the lowest concentration (0.05%) tested. In testswithout the feeding stimulant, mortality was less than 20%. Mortalityhere is due to the normal feeding behavior of the beetle whereby it willeventually need food and feed compulsively on the starch/dye combinationand die, as shown in FIG. 2a. This test confirmed the advantage of usingboth a photoactive dye and a feeding stimulant in insecticidalformulations for CRW control.

Experiments were also carried out to determine the effect of lightintensity on SCR mortality exposed to dye (from 0.0001% to 0.1%).Exposure to fluorescent light (1/10 the intensity of sunlight) caused70% mortality in 24 hours at 0.1% dye concentrations (FIG. 3). The LD₅₀at 24 hours for adult corn rootworms exposure to dye was calculated at0.07%.

Since the photoactivation of the dye is directly proportional to lightintensity, exposure for 1 hour to direct sunlight caused more than 90%mortality at the 0.1% concentration and by 21.5 hours more than 90% ofthe beetles were dead at the 0.01% and 0.1% dye concentration. Resultsare shown in FIG. 4.

Field cage studies were also carried out where corn plants were treatedwith applications of the insecticidal composition and placed in cages.The composition comprised starch (5%), feeding stimulant (5%), dye(0.06%) and a polymer emulsion (1-3%) to serve as an adherent orsticking agent. An additional cage containing the solution without dyeor feeding stimulant served as the control. One hundred fifty WCR adultswere released into each cage, exposed to insectidal samples for 48hours, then removed and counted. Mortality averaged 81% (19% survival)in the treatment cages and 1% (99% survival) in the control cage. Inaddition, samples of bait which was aged in the field for 6 days caused83% mortality (17% survival) in laboratory experiments. A subsequenttest was carried out where the feeding stimulant concentration wasreduced to 0.25% and the exposure period was increased to 6 days.Mortality averaged 85% (15% survival) in the treatment cages and 9% (91%survival) in the control.

It has thus been demonstrated that a composition comprising at least onephotoactive xanthene-type dye and a feeding stimulant in aqueoussolution is effective as an insecticide against diabroticite beetles.Both larval and adult stages are susceptible to insecticidal activityexhibited by the formulation. The composition may additionally includeadditives such as adherents of sticking materials, emulsifiers,thickeners, stabilizers, preservatives, antifoam agents and/or buffers.Effective dyes include but are not limited to phloxine B, rose bengal,erythrosin B and eosin, and they may be used alone or in combination. Apreferred dye is phloxine B, a xanthene dye registered as D&C (Drug andCosmetic) Red Dye #28 for use as a color additive in drugs and incosmetics by the Food and Drug Administration. The dyes are commerciallyavailable, e.g. Sure-Dye (Photodye International, Starkville, Miss.).

Cucurbitacins are the recommended feeding stimulant and are known anddescribed in the art for that purpose (see Metcalf et al., 1987, supra;Rhodes et al. 1980. J. Am. Soc. Hort. vol. 105, pp. 838-842; Metcalf etal. 1981. Cucurbit Genet. Coop. Rep. vol. 4, pp. 37-38; Metcalf, R. L.1985. Bull. Ill. Natl. Hist. Surv. vol. 33, pp. 175-198; Metcalf andRhodes, Canadian Patent 1,195,922, 1985; How et al. EnvironmentalEntomol. vol. 5, pp. 1042-1048, all herein incorporated by reference).The compounds may be obtained by extraction from Cucurbitaceae plants.The plant material may be dehydrated, then ground into a powderymaterial, or it may be ground up, the solid material filtered off andthe filtrate utilized. The bitter mutant of hawkesbury watermelon (BHW),Citrullus vulgaris Schrad, is an example of a plant material whichcontaining cucurbitacins which are effective as a feeding stimulant. Themelon may be ground to a pulp and the juice extracted. The extractionmay be carried out under pressure as in a cider or hydraulyic press,then filtered and utilized directly as a crude liquid extract. It mayalso be frozen for long-term storage (i.e. months). The juice can alsobe concentrated by evaporation, spray-drying, freeze-drying or othermeans to about 3-6% initial weight. Alternatively, cucurbitacins arecommercially available, although they are at present somewhat expensive.Although the cucurbitacins are generally used as a mixture of thevarious related compounds, investigations have been carried out todetermine the most effective. It was found that cucurbitacin E-glycosidewas the most abundant cucurbitacin in BHM and had the most powerfuleffect of the cucurbitacin compounds.

The insecticidal composition is prepared by mixing the feeding stimulantconcentrate with water to the desired concentration. An effectivefeeding stimulant concentration is from about 0.001% to about 10% (w/v).The toxicant is then added with mixing to the feeding stimulantsolution. An effective toxicant concentration is from about 0.025% (w/v)to about 5% (w/v) of aqueous solution. The various additives may also bemixed into the solution at this point. The concentrations of theseadditives may vary widely, depending on the requirements necessitated byclimate, temperature, field conditions, application method, etc., andthese amounts are easily determined by one of skill in the art. Forexample, a useful formulation may be prepared by combining a crudeextract of the BHM at a concentration of from about 0.001% to about 10%(w/v) with phloxine B at a concentration of about 0.0003% to about0.01%. [NOTE: The phloxine B concentration could vary according to theapplication method. For example, a concentration of about 0.0003% toabout 0.002% (w/v) in a volume of 20 gal/acre applied in an aqueoussolution by conventional spray equipment, such as tractor-mounted boomsprayers, backpack sprayers, etc. would be effective, while aconcentration of about 0.002% to about 0.01% (w/v) in a volume of 4gal/acre would be effective for aerial application.] A water solublestarch or other thickening agent, such as Mira Sperse 626 (A. E. StaleyMfg. Co., Decatur, Ill.) may be added at a concentration of from about1% to about 5% (w/v), and a sticker such as Gelva (Monsanto Corp, St.Louis, Mo.) may be added at a concentration of from about 1% to about 3%(w/v).

The composition is applied to target plants (corn, curcubits, peanutsand other agricultural crops attacked by the CRW) by conventionalspraying means. It is applied to cucurbits, for example, at the firstsign of CRW adults, usually at the early seedling stage. Treatments areapplied weekly for about 3 weeks or until adult CRW populations declinebelow economic injury levels. In corn, treatment may begin at firstevidence of adults present on corn or at the time of silking. Weeklytreatments continue for about 3 weeks or until the population of adultsdeclines below the economic injury levels. Trap collections and/orcounts of living and dead beetles in the treated corn may be utilized toestimate population levels.

The following examples are intended only to further illustrate theinvention and are not intended to limit the scope of the invention asdefined by the claims.

EXAMPLES Example 1

Effect of Feeding Stimulant and Dye on CRW.

In petri dishes, three replications of 10 SCR (mixed sex) were giveneither 10% starch and distilled water, 10% starch and 10% feedingstimulant (FS), 10% starch and 5% dye or a combination of 10% starch,10% FS and 5% dye. The petri dishes were placed in a growth chamberabout four inches under lights (5200-5900 lux). At 24 hours, the percentof live adults was determined as follows: starch and water, 100%; starchand FS, 97%; starch and dye, 70%; and starch, FS and dye, 7%.

Example 2

Effects of Varying Dye Concentrations in Aqueous Starch Solutions (Withand Without FS) and Different Types of Light.

SCR were exposed to five concentrations of dye (5%, 1%, 0.5%, 0.1%0.05%) in aqueous starch solutions (1-5%, w/v), both with and without FSin the procedure described in Example 1. At 24 hours, on 0.5% dye themortality was 83% dead from dye and FS, while it was 6% dead from dyeand water.

Using reduced dye concentrations of 0.1%, 0.01%, 0.001% and 0.0001%under the same conditions and with 10% FS, at 24 hours the percent oflive adults was 13%, 30%, 97% and 97%, respectively.

Using the reduced dye concentrations with 10% FS and 15 SCR per petridish, dishes were exposed to direct sun (about 72-95,000 lux) for atotal of 21/2 hours. At 24 hours, the percent of live adults was 0.2%,100% and 98%, respectively.

Example 3

Choice Test with Variable and Reduced Concentrations of FS.

In a choice test, adult WCR (5♂and 5♀) were placed in petri dishescontaining a treatment ball of 10% starch, 0.06% dye and one of 7concentrations of FS and a dye-free, FS-free ball. The FS concentrationstested were 5%, 4%, 3%, 2%, 1%, 0.5% and 0.25%. Two FS-free controlswere utilized: control 1 having a starch only and a starch/dye ball, andcontrol 2 having 2 starch only balls. Each treatment was replicated 3times. All dishes received 30-min exposure to direct sun (106,000-63,500lux). At all other times, dishes were kept 18 inches under fluorescentlamps. At 24 hours, the percent of live adults at 5%, 4%, 3%, 2%, 1%,0.5%, 0.25%, control 1 and control 2 was 0, 3%, 0, 3%, 0, 3%, 3%, 83%and 97%, respectively.

Example 4

Field Cage Study on Corn.

An insecticidal composition containing 0.25% FS and 0.06% dye wasprepared according to the following procedure: 0.12±0.001 g phloxine B(SureDye, PhotoDye International, supra), 20 ml Gelva multipolymeremulsion (Monsanto, supra) and 10 ml of a 5% (w/v) solution containingcrude extract of BHM (Citrullus vulgaris Schrad) were added withstirring to 60 ml distilled water in a 250-ml beaker. Ten grams ofstarch (Mira-Sperse 626, supra) was added and mixed thoroughly.Additional distilled water was added to bring the volume up to 200 ml.An additional 100 ml of the above mixture without the dye and FS wasalso prepared.

Four 6'×6' field cages were assembled and placed in plots of sweet corn.Cages 1, 2 and 3 contained 16, 19 and 16 plants, respectively. Controlcage 4 contained 18 plants. Approximately 150 one-week-old WCR adults(75 each of ♂ and ♀) were released into the cages. The mixtures wereapplied to the plants enclosed inside the cages using a Spraymaster, achemically-resistant high-volume adjustable hand sprayer (ConsolidatedPlastics Co., Inc., Twinsburg, Ohio). Each plant was sprayed along thestem, from the mid-point of the plant upward. Approximately 50 ml of themixture was applied in each cage. The application was carried out atapproximately 1:00 P.M., at a temperature of about 86° F., on a sunnyday. Light readings were taken at the time of release of the beetleswith an Extech Instruments light meter: at tassel height, the lightintensity measured 56,500 lux inside the cage and 99,00 lux outside.

At six days post-treatment, beetles were collected from the cages andcounted. On each plant the tassels were bent over and shaken, and allleaves pulled down to expose and dislodge any hidden WCR. Mortalityaveraged 85% in the treated cages and 9% in the control.

We claim:
 1. An insecticidal composition comprising a toxicant and afeeding stimulant in an aqueous solution in amounts effective for thecontrol of Diabroticite insects, wherein said toxicant is a xanthene dyeselected from the group consisting of phloxine B, rose bengal,erythrosin B and eosin, and said feeding stimulant is acucurbitacin-containing material.
 2. The insecticidal composition ofclaim 1, wherein said xanthene dye is phloxine B.
 3. The insecticidalcomposition of claim 1, wherein said composition further comprises atleast one additive selected from the group consisting of adherents,thickeners, emulsifiers, stabilizers, preservatives, anti-foam agentsand buffers.
 4. The insecticidal composition of claim 1, wherein saidtoxicant is present in an amount from about 0.025% (w/v) to about 5%(w/v) of aqueous solution.
 5. The insecticidal composition of claim 4,wherein said toxicant is present in an amount from about 0.1% (w/v) toabout 0.5% (w/v) of aqueous solution.
 6. The insecticidal composition ofclaim 1, wherein said feeding stimulant is present in an amount fromabout 0.001% (w/v) to about 10% (w/v).
 7. The insecticidal compositionof claim 6, wherein said feeding stimulant is present in an amount offrom about 1% (w/v) to about 5% (w/v).
 8. The insecticidal compositionof claim 1, wherein said composition further comprises a thickener andwherein said thickener is a starch.
 9. The insecticidal composition ofclaim 1, wherein said composition further comprises an adherent.
 10. Theinsecticidal composition of claim 1, wherein said composition furthercomprises an adherent and a thickener, wherein said thickener is astarch.
 11. The insecticidal composition of claim 1, wherein saidDiabroticite insects are corn rootworms.
 12. A method for the control ofDiabroticite insects, said method comprising applying a sufficientamount of an insecticidal composition to control said insects, whereinsaid insecticidal composition comprises a toxicant and a feedingstimulant in an aqueous solution in amounts effective for the control ofDiabroticite insects, wherein said toxicant is a xanthene dye selectedfrom the group consisting of phloxine B, rose bengal, erythrosin B andeosin, and said feeding stimulant is a cucurbitacin-containing material.13. The method of claim 12, wherein said photoactive xanthene dye isphloxine B.
 14. The method of claim 12, wherein said insecticidalcomposition further comprises at least one additive selected from thegroup consisting of adherents, thickeners, emulsifiers, stabilizers,preservatives, anti-foam agents and buffers.
 15. The method of claim 12,wherein said insecticidal composition further comprises a thickener andwherein said thickener is a starch.
 16. The method of claim 12, whereinsaid insecticidal composition further comprises an adherent.
 17. Themethod of claim 12, wherein said insecticidal composition furthercomprises and adherent and a thickener, wherein said thickener is astarch.
 18. The method of claim 12, wherein said Diabroticite insectsare corn rootworms.